221221019993 has 2 divisors, whose sum is σ = 221221019994. Its totient is φ = 221221019992.

The previous prime is 221221019909. The next prime is 221221020173. The reversal of 221221019993 is 399910122122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216212910169 + 5008109824 = 464987^2 + 70768^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221221019993 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 221221019993.

It is not a weakly prime, because it can be changed into another prime (221221015993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610509996 + 110610509997.

It is an arithmetic number, because the mean of its divisors is an integer number (110610509997).

Almost surely, 2^221221019993 is an apocalyptic number.

It is an amenable number.

221221019993 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221019993 is an equidigital number, since it uses as much as digits as its factorization.

221221019993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 41.

The spelling of 221221019993 in words is "two hundred twenty-one billion, two hundred twenty-one million, nineteen thousand, nine hundred ninety-three".